Pressure resistance controlled polishing apparatus



May 10, 1960 "r. DOMBROWSKI PRESSURE RESISTANCE CONTROLLED POLISHING APPARATUS Filed Aug. 2, 1955 S Sheets-Sheet 1 May 10, 1960 T. DOMBROWSKI PRESSURE RESISTANCE CONTROLLED POLISHING APPARATUS Filed Aug. 2, 1955 3 Sheets-Sheet 2 y 1960 T. DOMBROWSKI 2,935,784

PRESSURE RESISTANCE CONTROLLED POLISHING APPARATUS Filed Aug. 2, 1955 3 Sheets-Sheet 3 PRESSURE RESISTANCE CONTROLLED PQLHSHEWG APPARATUS Theodor D'ombrowski, Erkelenz, Rhineland, Germany,

assignor to Wilhelm Hegenscheidt Kommanditgesellschatt, Erkeienz, ineland, Germany This invention relates to an apparatus for polishing or burnishing of circular-section workpieces deviating from a strictly cylindricalshape. Considerable difficulties are encountered in roller polishing or burnishing workpieces in the form of bodies of revolution which deviate from a strictly cylindrical shape, since the contact pressure between the polishing rollers and the workpiece tends to vary continuously with the variations of the inclination of the portions to be polished to the workpiece axis.

It is an object of the invention to provide an automatic control of the polishing rollers during polishing of circular-section workpieces deviating from a cylindrical shape, if necessary with varying specific contact pressure of the rollers at various points of the workpiece to be rolled.

It is a further object of the present invention to adjust the transverse position of the polishing means or the atent 0 polishing rollers by means of a few and simple parts so tively associated with the moving means and the polishing means for adjusting the transverse position of the latter in such a manner that this transverse position is a function of the resistance offered by the polishing means to the moving means during axial movement of the polishing means as a result of different cross-sectional configurations of the workpiece'throughout its axial length.

By automatically adjusting the transverse position of the polishing means or polishing rollers a substantially uniform contact pressure between the rollers and the workpieces is obtained so that perfectly polished surfaces can be produced with the apparatus of the present invention.

Of importance equal to that of good surface and the.

accurate maintenance of the geometric shape of the workpiece is the improvement of the fatigue strength of the workpiece during the polishing operation, which depends upon the specific surface pressures applied at the point of contact. The specific surface pressure will depend upon the shape of the roller and of the workpiece at the point of contact and further upon the operational pressure of the roller. While the shape of the roller and of the workpiece are given factors, it is possible to adjust the force with which the rollers are pressed against the workpiece. In polishing bodies of revolution of non-cylindrical shape the contact pressure between the polishing roller and the workpiece will change with the inclination of the surface area to be polished to the workpiece axis from a pressure in radial direction to apressure in axial direc tion, that is the direction of pressure between roller and workpiece may change through an angle of 90. The- 2,935,784 Patented May 10, 1960 transverse position of the polishing rollers has therefore to be changed in such a way that despite the change of direction of the contact pressure this contact pressure between workpiece and polishing roller remains substantially constant.

In short, the apparatus in accordance with the invention presents the following four main advantages:

( 1) High geometric accuracy,

(2) Great economy in polishing workpieces of small diameter,

(3) Accurate and predeterminable control of the operational contact pressure of the rollers at every point of the surface to be polished,

(4) Consequently, uniformly high surface quality at every point of the workpiece.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which: i

Fig. 1 is a schematic partly sectioned side view of one embodiment constructed in accordance with the invention,

Fig. 2 is a cross-section, taken along the line A--A of Fig. 1,

Fig. 3 is a partial, partially sectioned side view showing a further embodiment of the apparatus of the present invention,

Fig. 4 is a side elevation of the embodiment shown in Fig. 3,

Fig. 5 is a longitudinal section through yet another em bodiment of the apparatus constructed in accordance with the invention,

Fig. 6 is a cross-section taken along the line CC* mounted ou guides 7 and 8 of the frame and is driven by a spindle 10, which cooperates with a nut mounted in the slide 9. Levers 11 and 12 are pivotally mounted intermediate the ends thereof on the carriage 9. Polishing rollers 13 and 14 are respectively mounted for rotation about their axes on the upper free ends of levers 11 and 12. The lower ends of levers 11, 12 are bifurcated and respectively pivotally connected to a rod-shaped projection extending from the right side, as viewed in Fig. 2, of a cylinder 15 and to the piston rod of a piston 16 which is slidably arranged in the cylinder 15. The feed spindle 10 is driven by a motor 17 by way of a gearing 18. The'feed spindle 10 is journalled at the right end thereof, as viewed in Fig. 1, in a bearing 19 for rotation about its axis and for movement in axial direction relative to the bearing 19. The left end of the feed spindle 10 is turnably mounted in a bearing formed on the right end of a piston rod 20 and the left end of the spindle 10 is connected to piston rod 20 for simultaneous movement therewith in axial direction. The cylinder 21 is mounted on the frame 1. The right-hand side 22 of the cylinder 21 is connected by means of a conduit A with the left-hand side'23'of the cylinder 15. Oil un-' der pressure is fed throughthe conduit B from the oil v pump'24 into the cylinder 15 to the right'side (as viewed.

in Fig. 2) of a piston 16 slidable therein. The side 22 of the cylinder 21 has twice as large a cross-sectional area as the side 23 of the cylinder 15 (although such a ratio is not absolutely essential). The carriage 9 is driven by the spindle 10 in the direction of the arrow 28. The workpiece 25 is centered and clamped between the main spindle 3 and the tailstock 26. The motor 4 rotates the spindle 3 and the workpiece 25. The rollers 13 and. 14 are urged against the workpiece 25 by means of the cylinder 15 into which oil under pressure is fed by the pump 24; During polishing of cylindrical workpieces, a pump pressure P1 exists on the right-hand side of the cylinder 15, whereas on the left-hand side 23, a pressure P2 will result from the inertia of the carriage 9.

The pressure. difference. on the opposite surfaces of the piston 16 acts as the operational pressure on the rollers. When the polishing rollers 13, 14 start to polish a fillet on the workpiece, as for instance shown at the left end of the workpiece 25 as viewed in Fig. l, the axial pressure between rollers 13, 14 and the workpiece 25 is increased, the carriage 9 is thereby held back, and the spindle 10 will move to the right as viewed in Fig. 1. This moves the piston in the cylinder 21 connected by the piston rod to the left end of the spindle 10 also to the right so that oil is pressed from the space 22 of the cylinder 21 through the conduit A into the space 23 of the piston 15, whereby the pressure P2 in the space 23 is increased, while the pressure P1 remains the same. Consequently the contact pressure of the rollers 13, 14 against the workpiece is decreased. In this way the 65, then the piston 61 is subjected to oil under pressure transverse position of the polishing rollers 13, 14 is adjusted as a function of the resistance offered by the polishing rollers to the moving means during the axial movement of the polishing rollers. it will be readily apparent that if the polishing rollers 13,

14 will come in contact with a surface of the workpiece which is normal to the workpiece axis and to the direction of the feed of the carriage 9, the axial pressure between workpiece and polishing rollers will reach its maximum and the radial contact pressure will be decreased to practically zero. In this event the polishing rollers 13, 14 will be spread apart to the maximum possible distance. When this position is reached a hand operated valve 27 cooperating with the conduit A may be closed, so that the pressure P on the left side of the piston 16 in the cylinder 15 is maintained and the rollers 13, 14 are held at the maximum distance from each other, in which position the carriage 9 may then be returned to its starting position while the rollers 13, 14 are held out of contact with the workpiece.

In the embodiment shown in Figs. 3 and 4, a carriage 51 slides in the machine frame 50. It is driven by a spindle 52 which is rotatably but axially non-displaceably mounted in the machine frame 50. The spindle 52 and the workpiece 53 are driven by means of a drive.

not shown in the drawing. On the carriage 51 is slidably mounted a longitudinal slide 54 and a cylinder 55 is fixedly attached to carriage 51. The longitudinal slide 54 is rigidly connected with a piston 56, which slides in the cylinder 55. On the longitudinal slide 54 there is slidably mounted a transverse slide 57, which may be transversely displaced by means of a spindle 58. A cylinder 69 is mounted on the transverse slide 57, on which a parallel slide 59 is also slidably mounted. The parallel slide 59 is rigidly connected with a piston 61 which moves within the cylinder 60. A polishing roller 62 is mounted for rotation about the axis, but not movable in axial direction on the parallel slide 59. The piston 61 is subjected on its left-hand side to oil pressure which is supplied by an oil pressure pump 63. The right- =hand side of the cylinder 60 communicates with the lefthand side of the cylinder 55 by means of the pipe 64. The pipe 64, the right-hand side of the cylinder 60 and the left-hand side of the cylinder 55 are filled with oil.

From the above from the oil pump 63, and the roller 62 is urged against the cylindrical part of the workpiece 53. In the pipe line 64 exists a pressure corresponding to the feed resistance, which is low as long as the roller 62 operates on cylindrical areas of the workpiece. In the same way as explained in connection with the embodiment shown in Figsui and 2, when the polishing roller 62 starts to work on a fillet of the workpiece 53, as for instance shown on the right side thereof as viewed in Fig. 3, the axial pressure between roller 62 and the workpiece 53 is increased, the slide 54 tends to move towards the left, as viewed in Fig. 3 moving thereby the piston 56 in the cylinder 55 towards the left, so that oil is pressed through the conduit 64 into the cylinder 60 at the right side of the piston 61 therein. Thereby, the radial contact pressure between rollers 62 and workpiece 53 is decreased.

In the embodiment according to Figs. 5, 6, 7, the feed spindle 30 is turnably mounted but axially non-displaceable in the frame of the machine and cooperates with a nut 31, which is mounted non-rotatable and axially nondisplaceable, but transversely dispiaceable in both directions in a bearing body 32. The bearing body 32 is mounted slidably in the transverse direction and axially non-displaceable in the carriage 33. The carriage 33 ment transversely to the machine axis. Levers 34, 35 abut with their side faces against corresponding faces 36 of the slide 33 and are thus axially retained. At the free ends of the levers 34 and 35 are mounted roller 37 and 38 which are rotatable but axially non-displaceable. The two levers 34, 35 are urged against the workpiece by means of a common spring 39. The bearing body 32 has sliding surfaces 40 inclined axially relative to the machine, against which abut slide blocks 41 fixed to the levers 34 and 35, which transmit the feed force of the spindle 30 to the slide 33.

As long as the rollers 37, 38 work on a cylindrical portion of the workpiece only a slight axial force is required for movement of the carriage 33 in axial direction. During this part of the operation the spring 39 will urge the rollers 37, 38 in contact with the workpiece. When the rollers 37, 38 start to act on a fillet of the workpiece as for instance shown at the left end thereof, as viewed in Fig. 5, the axial pressure between rollers and the workpiece will increase and. the slide blocks 41 will slide against the surfaces 40. Thereby, the rollers are spread apart against the action of the spring 39 so that the radial contact pressure between rollers and workpiece is decreased. As explained before, the radial pressure will decrease to practically zero when the rollers contact a surface area of the workpiece which is normal to the axis thereof. In such a case the carriage 33 will be prevented from moving in axial direction while the rollers 37, 38 are constantly forced further apart.

I claim:

1. A polishing apparatus for polishing a workpiece in the form of a non-cylindrical body of revolution and having a longitudinal axis, comprising, in combination, support means; polishing means mounted on said support means for movement relative to the work piece supported thereby in both axial and transverse directions of the work piece; first and second moving means operatively associated with said polishing means for moving the same in said axial and transversedirections, respectively; and

means interconnecting said first and second moving means for adjusting the transverse position of said polishing means in such a manner that the same is normally maintained in engagement with the outer surface of the work piece and also in such a manner that when the resistance ofiered by said polishing means to said first moving means during axial movement of said polishing means is increased as the result of increasing diameter of the work piece, said second moving means moves said polishing means away from the Work piece axis, as well as that when the resistance offered is decreased as the result of decreasing diameter of the Work piece, said second moving means moves said polishing means toward the work piece axis.

2. A polishing apparatus for polishing a workpiece in the form of a non-cylindrical body of revolution and having a longitudinal axis, comprising, in combination, support means; a carriage-mounted on said support means for movement relative thereto in the direction of said axis; at least one polishing element mounted on said carriage for movement therewith in said axial direction and for movement relative thereto transverse to said axis; first moving means for moving said carriage together with said polishing element in said axial direction, said first moving means including a spindle threadedly engaging said carriage for linearly displacing the same during rotation of said spindle; second moving means for moving said polishing element relative to said carriage in said transverse direction, said second moving means including a first hydraulic device; and hydraulic means interconnecting said spindle and said first hydraulic device for adjusting the transverse position of said polishing element,

said hydraulic means including a second hydraulic de' vice attached to said spindle in such a manner that axial pressures exerted thereon are transmitted to said second hydraulic device, and conduit means for placing said first and second hydraulic devices in communication with each other in sucha manner that when during movement of said carriage the resistance offered thereby to said spindle is increased as the result of the fact that said polishing element engages a thicker axial portion of the work piece, said second hydraulic device moves said polishing element transversely away from the work piece and that when the resistance is decreased as a result of the fact that said polishing element engages a thinner axial portion of the work piece, said second hydraulic device moves said polishing element transversely toward the work piece.

References'Cited in the file of this patent UNITED STATES PATENTS Crane July 17, 

